feat: plugin system with hooks pipeline and bundled plugins

rust/crates/plugins/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "plugins"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+publish.workspace = true
+
+[dependencies]
+serde = { version = "1", features = ["derive"] }
+serde_json.workspace = true
+
+[lints]
+workspace = true

rust/crates/plugins/bundled/example-bundled/.claw-plugin/plugin.json

@@ -0,0 +1,10 @@
+{
+  "name": "example-bundled",
+  "version": "0.1.0",
+  "description": "Example bundled plugin scaffold for the Rust plugin system",
+  "defaultEnabled": false,
+  "hooks": {
+    "PreToolUse": ["./hooks/pre.sh"],
+    "PostToolUse": ["./hooks/post.sh"]
+  }
+}

rust/crates/plugins/bundled/example-bundled/hooks/post.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+printf '%s\n' 'example bundled post hook'

rust/crates/plugins/bundled/example-bundled/hooks/pre.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+printf '%s\n' 'example bundled pre hook'

rust/crates/plugins/bundled/sample-hooks/.claw-plugin/plugin.json

@@ -0,0 +1,10 @@
+{
+  "name": "sample-hooks",
+  "version": "0.1.0",
+  "description": "Bundled sample plugin scaffold for hook integration tests.",
+  "defaultEnabled": false,
+  "hooks": {
+    "PreToolUse": ["./hooks/pre.sh"],
+    "PostToolUse": ["./hooks/post.sh"]
+  }
+}

rust/crates/plugins/bundled/sample-hooks/hooks/post.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+printf 'sample bundled post hook'

rust/crates/plugins/bundled/sample-hooks/hooks/pre.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+printf 'sample bundled pre hook'

rust/crates/plugins/src/hooks.rs

@@ -0,0 +1,395 @@
+use std::ffi::OsStr;
+use std::path::Path;
+use std::process::Command;
+
+use serde_json::json;
+
+use crate::{PluginError, PluginHooks, PluginRegistry};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum HookEvent {
+    PreToolUse,
+    PostToolUse,
+}
+
+impl HookEvent {
+    fn as_str(self) -> &'static str {
+        match self {
+            Self::PreToolUse => "PreToolUse",
+            Self::PostToolUse => "PostToolUse",
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct HookRunResult {
+    denied: bool,
+    messages: Vec<String>,
+}
+
+impl HookRunResult {
+    #[must_use]
+    pub fn allow(messages: Vec<String>) -> Self {
+        Self {
+            denied: false,
+            messages,
+        }
+    }
+
+    #[must_use]
+    pub fn is_denied(&self) -> bool {
+        self.denied
+    }
+
+    #[must_use]
+    pub fn messages(&self) -> &[String] {
+        &self.messages
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct HookRunner {
+    hooks: PluginHooks,
+}
+
+impl HookRunner {
+    #[must_use]
+    pub fn new(hooks: PluginHooks) -> Self {
+        Self { hooks }
+    }
+
+    pub fn from_registry(plugin_registry: &PluginRegistry) -> Result<Self, PluginError> {
+        Ok(Self::new(plugin_registry.aggregated_hooks()?))
+    }
+
+    #[must_use]
+    pub fn run_pre_tool_use(&self, tool_name: &str, tool_input: &str) -> HookRunResult {
+        self.run_commands(
+            HookEvent::PreToolUse,
+            &self.hooks.pre_tool_use,
+            tool_name,
+            tool_input,
+            None,
+            false,
+        )
+    }
+
+    #[must_use]
+    pub fn run_post_tool_use(
+        &self,
+        tool_name: &str,
+        tool_input: &str,
+        tool_output: &str,
+        is_error: bool,
+    ) -> HookRunResult {
+        self.run_commands(
+            HookEvent::PostToolUse,
+            &self.hooks.post_tool_use,
+            tool_name,
+            tool_input,
+            Some(tool_output),
+            is_error,
+        )
+    }
+
+    fn run_commands(
+        &self,
+        event: HookEvent,
+        commands: &[String],
+        tool_name: &str,
+        tool_input: &str,
+        tool_output: Option<&str>,
+        is_error: bool,
+    ) -> HookRunResult {
+        if commands.is_empty() {
+            return HookRunResult::allow(Vec::new());
+        }
+
+        let payload = json!({
+            "hook_event_name": event.as_str(),
+            "tool_name": tool_name,
+            "tool_input": parse_tool_input(tool_input),
+            "tool_input_json": tool_input,
+            "tool_output": tool_output,
+            "tool_result_is_error": is_error,
+        })
+        .to_string();
+
+        let mut messages = Vec::new();
+
+        for command in commands {
+            match self.run_command(
+                command,
+                event,
+                tool_name,
+                tool_input,
+                tool_output,
+                is_error,
+                &payload,
+            ) {
+                HookCommandOutcome::Allow { message } => {
+                    if let Some(message) = message {
+                        messages.push(message);
+                    }
+                }
+                HookCommandOutcome::Deny { message } => {
+                    messages.push(message.unwrap_or_else(|| {
+                        format!("{} hook denied tool `{tool_name}`", event.as_str())
+                    }));
+                    return HookRunResult {
+                        denied: true,
+                        messages,
+                    };
+                }
+                HookCommandOutcome::Warn { message } => messages.push(message),
+            }
+        }
+
+        HookRunResult::allow(messages)
+    }
+
+    #[allow(clippy::too_many_arguments, clippy::unused_self)]
+    fn run_command(
+        &self,
+        command: &str,
+        event: HookEvent,
+        tool_name: &str,
+        tool_input: &str,
+        tool_output: Option<&str>,
+        is_error: bool,
+        payload: &str,
+    ) -> HookCommandOutcome {
+        let mut child = shell_command(command);
+        child.stdin(std::process::Stdio::piped());
+        child.stdout(std::process::Stdio::piped());
+        child.stderr(std::process::Stdio::piped());
+        child.env("HOOK_EVENT", event.as_str());
+        child.env("HOOK_TOOL_NAME", tool_name);
+        child.env("HOOK_TOOL_INPUT", tool_input);
+        child.env("HOOK_TOOL_IS_ERROR", if is_error { "1" } else { "0" });
+        if let Some(tool_output) = tool_output {
+            child.env("HOOK_TOOL_OUTPUT", tool_output);
+        }
+
+        match child.output_with_stdin(payload.as_bytes()) {
+            Ok(output) => {
+                let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
+                let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
+                let message = (!stdout.is_empty()).then_some(stdout);
+                match output.status.code() {
+                    Some(0) => HookCommandOutcome::Allow { message },
+                    Some(2) => HookCommandOutcome::Deny { message },
+                    Some(code) => HookCommandOutcome::Warn {
+                        message: format_hook_warning(
+                            command,
+                            code,
+                            message.as_deref(),
+                            stderr.as_str(),
+                        ),
+                    },
+                    None => HookCommandOutcome::Warn {
+                        message: format!(
+                            "{} hook `{command}` terminated by signal while handling `{tool_name}`",
+                            event.as_str()
+                        ),
+                    },
+                }
+            }
+            Err(error) => HookCommandOutcome::Warn {
+                message: format!(
+                    "{} hook `{command}` failed to start for `{tool_name}`: {error}",
+                    event.as_str()
+                ),
+            },
+        }
+    }
+}
+
+enum HookCommandOutcome {
+    Allow { message: Option<String> },
+    Deny { message: Option<String> },
+    Warn { message: String },
+}
+
+fn parse_tool_input(tool_input: &str) -> serde_json::Value {
+    serde_json::from_str(tool_input).unwrap_or_else(|_| json!({ "raw": tool_input }))
+}
+
+fn format_hook_warning(command: &str, code: i32, stdout: Option<&str>, stderr: &str) -> String {
+    let mut message =
+        format!("Hook `{command}` exited with status {code}; allowing tool execution to continue");
+    if let Some(stdout) = stdout.filter(|stdout| !stdout.is_empty()) {
+        message.push_str(": ");
+        message.push_str(stdout);
+    } else if !stderr.is_empty() {
+        message.push_str(": ");
+        message.push_str(stderr);
+    }
+    message
+}
+
+fn shell_command(command: &str) -> CommandWithStdin {
+    #[cfg(windows)]
+    let command_builder = {
+        let mut command_builder = Command::new("cmd");
+        command_builder.arg("/C").arg(command);
+        CommandWithStdin::new(command_builder)
+    };
+
+    #[cfg(not(windows))]
+    let command_builder = if Path::new(command).exists() {
+        let mut command_builder = Command::new("sh");
+        command_builder.arg(command);
+        CommandWithStdin::new(command_builder)
+    } else {
+        let mut command_builder = Command::new("sh");
+        command_builder.arg("-lc").arg(command);
+        CommandWithStdin::new(command_builder)
+    };
+
+    command_builder
+}
+
+struct CommandWithStdin {
+    command: Command,
+}
+
+impl CommandWithStdin {
+    fn new(command: Command) -> Self {
+        Self { command }
+    }
+
+    fn stdin(&mut self, cfg: std::process::Stdio) -> &mut Self {
+        self.command.stdin(cfg);
+        self
+    }
+
+    fn stdout(&mut self, cfg: std::process::Stdio) -> &mut Self {
+        self.command.stdout(cfg);
+        self
+    }
+
+    fn stderr(&mut self, cfg: std::process::Stdio) -> &mut Self {
+        self.command.stderr(cfg);
+        self
+    }
+
+    fn env<K, V>(&mut self, key: K, value: V) -> &mut Self
+    where
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>,
+    {
+        self.command.env(key, value);
+        self
+    }
+
+    fn output_with_stdin(&mut self, stdin: &[u8]) -> std::io::Result<std::process::Output> {
+        let mut child = self.command.spawn()?;
+        if let Some(mut child_stdin) = child.stdin.take() {
+            use std::io::Write as _;
+            child_stdin.write_all(stdin)?;
+        }
+        child.wait_with_output()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{HookRunResult, HookRunner};
+    use crate::{PluginManager, PluginManagerConfig};
+    use std::fs;
+    use std::path::{Path, PathBuf};
+    use std::time::{SystemTime, UNIX_EPOCH};
+
+    fn temp_dir(label: &str) -> PathBuf {
+        let nanos = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .expect("time should be after epoch")
+            .as_nanos();
+        std::env::temp_dir().join(format!("plugins-hook-runner-{label}-{nanos}"))
+    }
+
+    fn write_hook_plugin(root: &Path, name: &str, pre_message: &str, post_message: &str) {
+        fs::create_dir_all(root.join(".claw-plugin")).expect("manifest dir");
+        fs::create_dir_all(root.join("hooks")).expect("hooks dir");
+        fs::write(
+            root.join("hooks").join("pre.sh"),
+            format!("#!/bin/sh\nprintf '%s\\n' '{pre_message}'\n"),
+        )
+        .expect("write pre hook");
+        fs::write(
+            root.join("hooks").join("post.sh"),
+            format!("#!/bin/sh\nprintf '%s\\n' '{post_message}'\n"),
+        )
+        .expect("write post hook");
+        fs::write(
+            root.join(".claw-plugin").join("plugin.json"),
+            format!(
+                "{{\n  \"name\": \"{name}\",\n  \"version\": \"1.0.0\",\n  \"description\": \"hook plugin\",\n  \"hooks\": {{\n    \"PreToolUse\": [\"./hooks/pre.sh\"],\n    \"PostToolUse\": [\"./hooks/post.sh\"]\n  }}\n}}"
+            ),
+        )
+        .expect("write plugin manifest");
+    }
+
+    #[test]
+    fn collects_and_runs_hooks_from_enabled_plugins() {
+        let config_home = temp_dir("config");
+        let first_source_root = temp_dir("source-a");
+        let second_source_root = temp_dir("source-b");
+        write_hook_plugin(
+            &first_source_root,
+            "first",
+            "plugin pre one",
+            "plugin post one",
+        );
+        write_hook_plugin(
+            &second_source_root,
+            "second",
+            "plugin pre two",
+            "plugin post two",
+        );
+
+        let mut manager = PluginManager::new(PluginManagerConfig::new(&config_home));
+        manager
+            .install(first_source_root.to_str().expect("utf8 path"))
+            .expect("first plugin install should succeed");
+        manager
+            .install(second_source_root.to_str().expect("utf8 path"))
+            .expect("second plugin install should succeed");
+        let registry = manager.plugin_registry().expect("registry should build");
+
+        let runner = HookRunner::from_registry(&registry).expect("plugin hooks should load");
+
+        assert_eq!(
+            runner.run_pre_tool_use("Read", r#"{"path":"README.md"}"#),
+            HookRunResult::allow(vec![
+                "plugin pre one".to_string(),
+                "plugin pre two".to_string(),
+            ])
+        );
+        assert_eq!(
+            runner.run_post_tool_use("Read", r#"{"path":"README.md"}"#, "ok", false),
+            HookRunResult::allow(vec![
+                "plugin post one".to_string(),
+                "plugin post two".to_string(),
+            ])
+        );
+
+        let _ = fs::remove_dir_all(config_home);
+        let _ = fs::remove_dir_all(first_source_root);
+        let _ = fs::remove_dir_all(second_source_root);
+    }
+
+    #[test]
+    fn pre_tool_use_denies_when_plugin_hook_exits_two() {
+        let runner = HookRunner::new(crate::PluginHooks {
+            pre_tool_use: vec!["printf 'blocked by plugin'; exit 2".to_string()],
+            post_tool_use: Vec::new(),
+        });
+
+        let result = runner.run_pre_tool_use("Bash", r#"{"command":"pwd"}"#);
+
+        assert!(result.is_denied());
+        assert_eq!(result.messages(), &["blocked by plugin".to_string()]);
+    }
+}